title: Speckle-scale focusing in the diffusive regime with time-reversal of variance-encoded light (TROVE).
abstract: Focusing of light in the diffusive regime inside scattering media has long been considered impossible. Recently, this limitation has been overcome with time reversal of ultrasound-encoded light (TRUE), but the resolution of this approach is fundamentally limited by the large number of optical modes within the ultrasound focus. Here, we introduce a new approach, time reversal of variance-encoded light (TROVE), which demixes these spatial modes by variance-encoding to break the resolution barrier imposed by the ultrasound. By encoding individual spatial modes inside the scattering sample with unique variances, we effectively uncouple the system resolution from the size of the ultrasound focus. This enables us to demonstrate optical focusing and imaging with diffuse light at unprecedented, speckle-scale lateral resolution of ~ 5 μm.
authors.affiliation: California Institute of Technology, 1200 E California Blvd, Pasadena CA 91125, USA ; London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Judkewitz
authors.forename: Ying Min
authors.initials: YM
authors.lastname: Wang
authors.forename: Roarke
authors.initials: R
authors.lastname: Horstmeyer
authors.forename: Alexandre
authors.initials: A
authors.lastname: Mathy
authors.forename: Changhuei
authors.initials: C
authors.lastname: Yang